This invention relates to an exchanging apparatus having message-waiting function, such as a key telephone system, and the control method of controlling the exchange, and a communication terminal apparatus having caller ID call-back function, such as a cellular communication terminal, and the control method.
The message-waiting function is equipped to an exchanging apparatus such as a key telephone system. According to the message-waiting function, a calling terminal which calls a destination terminal is registered as a candidate terminal to be called in accordance with an instruction when the destination terminal does not respond to the call. When an arbitrary terminal makes a massage-waiting call-back (MW call-back) request to return the calling to the calling terminal, the candidate terminal which called to the requesting terminal and registered to correspond to the requesting terminal is automatically called.
The conventional exchanging apparatus equipped with the message-waiting function is provided with a memory region capable of storing a plurality (four, for example) of extension terminals for each of extension terminals provided to the apparatus. The plurality of registered extension terminals each has called the corresponding extension terminal. When the called extension terminals makes a MW call-back request, the registered extension terminals are called in order of the registration.
The caller ID call-back function is equipped to a communication terminal apparatus such as a cellular communication terminal. According to the caller ID call-back function, when a communication terminal cannot respond to the calling, telephone numbers of calling terminals are informed from the network and stored. When the user of the called terminal issues a caller ID call-back request, the terminal automatically calls back to the calling terminal with use of the stored telephone number.
The conventional communication terminals equipped with the caller ID call-back function has a memory region for storing a plurality of telephone numbers informed from the network. When the caller ID call-back request occurs under the condition where a plurality of telephone numbers are stored in the memory region, the oldest one of the telephone numbers are used for the calling-back.
As should be clear from the above, according to the conventional exchanging apparatus and communication terminal apparatus, the user cannot call any registered terminals till the oldest one of the registered terminals responds to the call.
In view of this problem, there is developed an apparatus provided with the function for canceling the registration of the terminal registered at first, in response to the special cancel instruction. By using such a function, when the terminal registered first does not respond to the calling, the user can cancel the registration and call the other terminal registered in the memory.
If the above-mentioned canceling is executed, however, the registration of the first-registered terminal which does not respond to the calling but has not been connected with the user yet is canceled, and the user cannot execute the message-waiting response or the calling-back to the terminal the registration of which is canceled. Further, the user must issue a special instruction to cancel the registration, and the canceling operation is rather complicated. When the user does not remember the canceling operation, the user cannot cancel the registration.